What is This? A Bioluminescent Mushroom?

Hint: It's actually not on the ground, nor in the oceans, but up in the sky—way up in the sky.

Image courtesy of Professor Paul Woodward, Laboratory for Computational Science and Engineering, University of Minnesota

Answer: Stellar turbulence

This computer-rendered image depicts a Rayleigh-Taylor instability: a turbulent, gravity-driven mixing of fluids that occurs in stars (and in boiling water) when a heavy substance sits atop a lighter one.